Roof Pointing 

Where is roof pointing used? 

Roof pointing is commonly used at the following roof interfaces as a form of detailing or finishing:

1. Apex: roof pointing is used for ridge tiles, commonly using cement or lime mortar.
2. Verges: used to fill gaps between tiles and walls, this type of roof pointing is commonly done using cement or lime depending upon the nature of the building.
3. Valleys: used to infill gaps between lead valley linings and profiled tiles. Mortar should never be bedded directly onto lead, lead is a metal and expands and contracts, whereas mortar is inert and will not flex causing cracking and failure.
4. Chimneys: pointing brickwork using lime mortar is a common form of roof pointing. Some contractors use it to form flashings around chimneys, this is not advisable, lead flashings are best practice.
5. Eaves: In some instances, eaves using pantiles for example, may be bedded and neatly pointed. A mortar bed should be set back from the edge of the tile to prevent water entering any joints in the two materials.

Mortar Mixes for Roof Pointing 

Roof pointing mortars need to be weather-resistant, flexible, and durable. The mix you choose can affect how long your pointing lasts and how well it performs under heat, rain, and wind stress.

Re Posting Vs Re Bedding

In this instance, we have used roof pointing to ridge tiles as the example,. However, the same would apply to all interfaces where roof pointing methods are used.

Repointing Ridge Tiles

This involves removing old or damaged pointing and applying fresh mortar over the existing bedding.

Pros:

• Cost-effective: Typically cheaper than full rebedding
• Less disruptive: Faster, no need to remove and reset tiles
• Good for minor wear: Ideal when bedding is still structurally sound
• Aesthetic boost: Improves appearance and weather protection

Cons:

• Superficial fix: Won’t solve issues if bedding is loose or deteriorated
• Shorter lifespan: May not last as long as full rebedding if underlying mortar is failing
• Limited scope: Only addresses the outer layer, not the structural base

Rebedding Ridge Tiles

This process involves removing the ridge tiles, scraping away all old mortar, laying fresh bedding mortar, and then repointing.

Pros:

• Long-term solution: Rebuilds both structure and seal
• Addresses loose tiles: Critical if tiles are unstable or mortar is crumbling
• Better durability: Especially useful for older roofs or roofs exposed to harsh conditions

Cons:

• Higher cost: More labour-intensive, so usually more expensive
• More time-consuming: May require several days depending on roof size
• Not always necessary: Overkill if bedding is still intact

Which to Choose & When

NFRC Guidance (National Federation of Roofing Contractors)

The NFRC, the UK’s leading roofing trade association, provides clear guidance through technical bulletins (e.g., Technical Bulletin 33):

Key Points:

Mechanical Fixing: Mortar alone is not considered a secure method of fixing ridge or hip tiles. Tiles should also be mechanically fixed in accordance with BS 5534 (Code of Practice for Slating and Tiling).

Bedding and Pointing:

• Mortar should only be used for bedding, not as the primary fixing method.
• Pointing (the outer cosmetic finish) can be applied over bedding, but only for weather protection and aesthetics—not structural security.
• Modern flexible pointing compounds are encouraged for durability and movement accommodation.

Mortar Mixes:

• Recommended mix: 1 part cement, 3 parts sharp sand.
• Lime or plasticiser may be used to improve workability.
• Mortar should comply with BS EN 998-2.

NHBC Standards (National House Building Council – UK)

The NHBC provides warranty-backed building standards and their stance aligns with best practices for structural durability and compliance.

NHBC Requirements:

Mechanical Fixing Required: All ridge and hip tiles must be mechanically fixed in addition to mortar bedding (since 2015, following changes to BS 5534).

Mortar Bedding:

• Must be durable, well-compacted, and properly cured.
• Bedding must not be used where it cannot fully support tile loads or is exposed to movement.

Use of Flexible Mortars:

• NHBC encourages the use of proprietary flexible pointing systems for longevity.
• These materials must still be used in combination with mechanical fixings.

Alternatives to Traditional Roof Pointing 

When replacing a roof covering, compliance is crucial, and products that meet current guidelines and standards must be considered where appropriate and practical.

Roof Pointing Comparison Table 

The following comparison chart is a useful reference point when considering roof pointing applications. Detailing standards, longevity, cost and maintenance frequency.

Other Roof Pointing 

Pointing may be used in other areas on a roof. Examples include chimney stacks, flashing interfaces, and coping stones. 

Generally, lead flashings, wedges into masonry chases, should be sealed with a flexible joint adhesive to prevent cracking of the mortar mix as the lead expands and contracts. 

Chimney stacks should be pointed in lime mortar for the brick or stone joints, and flaunchings can be done using cement and grit sand for added strength and durability. 

Coping stones are usually bedded in cement mortar for strength and joints can be pointed using mastic sealants. However, copings in some instances may benefit from being capped in lead or even zinc to prevent water penetration. 

All of these services, and sound impartial advice, is available from GNR.